What evidence is used to underpin the design of strength-based exercise interventions evaluated in randomised controlled trials for rheumatoid arthritis? A systematic review protocol

INTRODUCTION: Healthcare researchers designing strength-based exercise interventions must choose an appropriate dose to test before evaluating its effect using a definitive/phase-III randomised controlled trial (RCT). Compared with early phase testing employed by pharmaceutical trials, it is questionable whether exercise-based trials employ the same rigour for establishing tolerated dosage. Consequently, it is unclear if participants are initially prescribed optimal doses of exercise, which may potentially impact on study outcomes. Using trials of strength-based exercise interventions in adults with rheumatoid arthritis (RA) as an exemplar, the aims of this review are to (1) identify the proportion of RCTs that use phase I/II trials with dose escalation methodology for setting prescription parameters, (2) determine type and level of evidence used to justify prescription parameters of strength-based exercise interventions evaluated by RCTs, (3) explore consistency and applicability of the evidence underpinning prescription parameters in RCTs and (4) explore if a relationship exists between risk of bias for RCTs evaluating strength-based interventions and the level of evidence used to underpin prescription parameters. METHODS AND ANALYSIS: Focusing on RCT’s evaluating strength-based exercise interventions in adults with RA published after 2000, the following databases will be searched: Allied and Complementary Medicine Database, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, Excerpta Medica Database, Medline and Physiotherapy Evidence Database. For each RCT, we will identify the evidence used to underpin prescription parameters. Both trial and underpinning evidence will have key information about the intervention extracted using the template for intervention description and replication checklist. Risk of bias will be assessed according to Cochrane. Levels of evidence will be assessed against the Oxford Centre for Evidence-Based Medicine and relationships between RCT and underpinning evidence explored and described narratively. Two independent assessors will be involved throughout data selection and extraction with recourse to a third reviewer should agreement not be reached. ETHICS AND DISSEMINATION: No ethical issues are identified. Dissemination will be via publication. PROSPERO REGISTRATION NUMBER: CRD42018090963.